My long-term goal is to study the biology of stromal-epithelial interactions in benign prostatic hyperplasia (BPH). Since development, growth and tumorigenesis in the prostate is closely regulated by the stromal-epithelial crosstalk, identifying the signal transduction pathways between prostate epithelial cells and the surrounding stromal cells will enable us to better understand the normal and abnormal biology in prostatic diseases. I hypothesize that expression of particular stromal genes is one of the components that regulates the proliferation, cell death and differentiation of prostatic epithelial cells leading to BPH in adulthood. The Jun-family proteins that are early transcription factor molecules have been shown to regulate stromal-epithelial interactions via paracrine modulation. Moreover, the Jun family member proteins have been shown to play an important role in proper development of the genitourinary organs. The balance between the different Jun-family expression in the stroma may be one of the determinants of the ultimate survival or death signals that the stroma may exert on prostatic epithelial cells. This proposal will address whether paracrine signals form stromal cells with genetically modified Jun-family proteins can regulate epithelial proliferation, cell death and differentiation. Stromal expression of Jun-family proteins will be examined in relation to signal transduction pathways known to be important in prostatic stromal-epithelial interactions. These studies can improve our understanding of normal and abnormal stromal-epithelial interactions that may lead to BPH in adulthood.